Bi-component fiber for the production of spunbonded fabric

Abstract

A bi-component fiber ( 1 ), in particular for the production of spunbond fabrics ( 4 ), with a first component ( 2 ) and a second component ( 3 ), whereby the first component ( 2 ) has a first polymer as an integral part and the second component has a second polymer as an integral part. The polymer of one of the two components ( 2, 3 ) has been polymerized with a metallocene catalyst and the polymer of the other component ( 2, 3 ) has been polymerized with a Ziegler-Natta catalyst and subjected to a subsequent visbreaking treatment.

What is claimed is: 
     
         1 . Bicomponent fiber for the production of spunbond fabrics, with a first component and a second component, whereby the first component has a first polymer as an integral part and the second component has a second polymer as an integral part,
 characterized in that   the polymer of one of the two components has been polymerized with a metallocene catalyst and in that the polymer of the other component has been polymerized with a Ziegler-Natta catalyst and subjected to a subsequent visbreaking treatment.   
     
     
         2 . Bicomponent fiber according to  claim 1 , characterized in that the difference between the melting points of the first component and the second component is less than or equal to 8° C. 
     
     
         3 . Bicomponent fiber according to  claim 1 , characterized in that the difference between the melting points of the first component and the second component is at most 6° C. 
     
     
         4 . Bicomponent fiber according to  claim 1 , characterized in that the difference between the melting points of the first component and the second component is between 1° C. to 8° C. 
     
     
         5 . Bicomponent fiber according to  claim 1 , characterized in that the difference between the melting points of the first component and the second component is between 1° C. to 6° C. 
     
     
         6 . Bicomponent fiber according to  claim 1 , characterized in that the component whose polymer has been polymerized with a metallocene catalyst forms an outer surface of the bicomponent fiber viewed in a cross-sectional direction of the fiber. 
     
     
         7 . Bicomponent fiber according to  claim 1 , characterized in that the component whose polymer has been polymerized with a metallocene catalyst completely surrounds the component whose polymer has been polymerized with a Ziegler-Natta catalyst. 
     
     
         8 . Bicomponent fiber according to  claim 1 , characterized in that the difference between melt-flow indices of the first component and the second component is less than or equal to 25 g/10 minutes. 
     
     
         9 . Bicomponent fiber according to  claim 1 , characterized in that the difference between melt-flow indices of the first component and the second component is less than or equal to 20 g/10 minutes. 
     
     
         10 . Bicomponent fiber according to  claim 1 , characterized in that the difference between melt-flow indices of the first component and the second component is 15 g/10 minutes. 
     
     
         11 . Bicomponent fiber according to  claim 1 , characterized in that melt-flow indices of the first component and the second component in each case are less than or equal to 50 g/10 minutes. 
     
     
         12 . Bicomponent fiber according to  claim 1 , characterized in that the melt-flow indices of the first component and the second component in each case are less than or equal to 40 g/10 minutes. 
     
     
         13 . Bicomponent fiber according to  claim 1 , characterized in that the first component has an additive, wherein the second component has a proportion by weight of the additive that is less than that in the first component. 
     
     
         14 . Bicomponent fiber according to  claim 1 , characterized in that the first component has an additive, wherein the second component has a proportion by weight of the additive that is at most 33.3% of the proportion by weight of the additive in the first component. 
     
     
         15 . Bicomponent fiber according to  claim 13 , characterized in that the additive is selected from the group of a primary antioxidant, a secondary antioxidant, a UV absorber, a UV stabilizer, a flame retardant, an antistatic agent, a lubricating agent, a metal deactivator, a hydrophilizing agent, a hydrophobizing agent, an anti-fogging additive, a biocide, and mixtures thereof 
     
     
         16 . Bicomponent fiber according to  claim 13 , characterized in that the additive is selected from the group of:
 sterically inhibited phenols, aromatic secondary or tertiary amines, aminophenols, aromatic nitro compounds or nitroso compounds, organic phosphites or phosphonates, thioethers, thioalcohols, thioesters, sulfides and sulfur-containing organic acids, dithiocarbamates, thiodipropionates, aminopyrazoles, metal-containing chelates, mercaptobenzimidazoles, hydroxybenzophenones, cinnamates, oxalanilides, salicylates, resorcinol, monobenzoates, benzotriazoles, triazines, benzophenones, titanium dioxide, carbon black, metal-containing complexes of organic sulfur compounds or phosphorus compounds, sterically hindered amines (HALS), metal hydroxides, borates, organic bromine-containing compounds or chlorine-containing compounds, organic phosphorus compounds, antimony trioxide, melamine, melamine cyanurate, expanded graphite or other intumescence systems, quaternary ammonium salts, alkyl sulfonates, alkyl sulfates, alkyl phosphates, dithiocarbamates, alkaline(-earth) metal carboxylates, polyethylene glycols, as well as their esters and ethers, ethoxylates, mono- and diglycerides, fatty alcohols, esters of fatty alcohols, fatty acids, fatty acid esters, dicarboxylic acid esters, fatty acid amides, metal salts of fatty acids, polyolefin waxes, natural or synthetic paraffins, and their derivatives, fluoropolymers and fluoroligomers, anti-blocking agents such as silicic acids, silicones, silicates, calcium carbonate, amides of monocarboxylic acids and dicarboxylic acids and their derivatives, cyclic amides, hydrazones, and bishydrazones, hydrazides, hydrazines, melamine and its derivatives, benzotriazoles, aminotriazoles, sterically inhibited phenols in connection with complexing metal compounds, benzyl phosphonates, pyridithiols, thiobisphenol esters, polyglycols, ethoxylates, fluoropolymers and fluoroligomers, montan waxes, in particular stearates, 10,10′-oxybisphenoxarsine (OBPA), N-(trihalo-methylthiol)phthalimide, tributyltin oxide, zinc dimethyl dithiocarbamate, diphenylantimony-2-ethyl hexanoate, copper-8-hydroxyquinoline, isothiazolones, silver and silver salts as biocides, and mixtures of the above-mentioned substances.   
     
     
         17 . Bicomponent fiber according to  claim 1 , characterized in that the first polymer is selected from the group of polyolefins, polyolefin-copolymers, ethylene polymers, ethylene-copolymers, propylene, butylene, hexene, octene, mixtures of the above-mentioned substances, and blends of the above-mentioned substances. 
     
     
         18 . Bicomponent fiber according to  claim 1 , characterized in that the second polymer is selected from the group of polyolefins, polyolefin-copolymers, ethylene polymers, ethylene-copolymers, propylene, butylene, hexene, octene, mixtures of the above-mentioned substances, and blends of the above-mentioned substances. 
     
     
         19 . Bicomponent fiber according to  claim 1 , characterized in that the proportion by weight of the component whose polymer has been polymerized with a metallocene catalyst is at most 50% in the bicomponent fiber. 
     
     
         20 . Spunbond fabric with at least one bicomponent fiber with a first component and a second component, whereby the first component has a first polymer as an integral part and the second component has a second polymer as an integral part, the polymer of one of the two components having been polymerized with a metallocene catalyst and the polymer of the other component having been polymerized with a Ziegler-Natta catalyst and subjected to a subsequent visbreaking treatment.